I'm actually in a very similar case to yours. I moved from a D300 with Sigma 18-50 2.8, Sigma 8-16, Sigma 70-200, and Nikon 35 f1.8. I purchased a D600 and a new Tamron 24-70, and I can say that this lens is a fantastic pairing with a full frame body. Tests have shown it to be as sharp as the Nikon 24-70 and I've been extremely impressed with sharpness even at f2.8.

The 35 works on full frame with some minor vignetting in the corners. The 8-16 doesn't work on full frame (maybe just barely at 16mm) but with DX does just fine.

Well, I was also really interested in the Tameron 24-70mm 2.8 but the onion shaped bokeh is just plently ugly. It would be great to compare the bokeh with VC on or OFF, maybe this would solve this problem...

I'm now in about 1,000 photos and haven't yet noticed bokeh distracting enough to take away from the subject. This is one of those things that just doesn't really matter in the real world, but I suppose reviewers need to find something to ding.